Linear motion guide units in recent years have become an integral element of a variety of machinery including machine tools, semiconductor fabricating equipment, measuring instruments, assembling machines, and so on. Thus, various linear motion guide units different in construction and size have been developed commercially in conformity with their usage. Advanced machinery of diverse sorts is expected to get more accuracy in operation and more stiff or rigid in mechanical strength even more miniature in construction than ever and, correspondingly, the linear motion guide units are also needed to meet with growing demands for high precision in operation, high stiffness in mechanical strength and yet more miniature in construction.
One example of the prior linear motion guide units is disclosed for example in commonly-assigned Japanese Laid-Open Patent Application H07-91 446. With the prior linear motion guide unit stated earlier, as shown in FIGS. 1 and 3 of the publication recited above, there is provided a retainer plate 5 to keep in place more than one roller and a binding strip 6 is provided to securely hold the retainer plate 5 against a carriage 3 in a snap-action manner. The binding strip 6 is made of metallic plate including steal or the like rich in resilient and made up of a lengthwise major part 31 to fit into a lengthwise groove 29 cut in the retainer plate 5, lengthwise opposite ends 32 of the major part 31 angled to extend away from a guide rail 1 so as to fit into notches cut into outward end surfaces of the end caps 4, and hooked pawls 33 at the extremities of the angled ends 33 heading for the end caps 4.
The binding strip in the linear motion guide unit constructed as stated earlier, however, is usually made straight or just curved as a whole. Such binding strip as recited earlier, when applied to the carriage 1.5 times or above longer than in the ordinary carriage, would get warped across a considerable length around either midway area or lengthwise opposite end areas and, as a result, fail to firmly hold down or fasten the retainer plate over the overall length thereof against the carriage.
Linear motion guide units have become in recent years an integral mechanical element of machinery, which is used installed in the relatively sliding parts in machinery. Accordingly, the linear motion guide units diverse in their sizes and types have been developed into commercial products for a variety of needs or applications. Nevertheless, advanced modern machines including machine tools, semiconductor manufacturing equipment, measurement instruments, assembling machines, and so on are needed to fit high accuracy of submicron levels in traveling operation and position control. To cope with this demand in machines, the linear motion guide units are also in pursuit of high stiffness or strength even miniature in construction.